Storage system group including scale-out storage system and management method therefor

ABSTRACT

A management system is coupled to a storage system group including a scale-out storage system (a virtual storage system). The management system has storage management information, which includes information denoting, for each storage system, whether or not a storage system is a component of a virtual storage system. The management system, based on the storage management information, determines whether or not a first storage system is a component of a virtual storage system, and in a case where the result of this determination is affirmative, identifies, based on the storage management information, a second storage system, which is a storage system other than the virtual storage system that includes the first storage system, and allows a user to perform a specific operation only with respect to this second storage system.

This is a continuation application of U.S. Ser. No. 12/988,008, filedOct. 15, 2010, which is a 371 of International Application NumberPCT/JP2010/063027, filed Aug. 2, 2010, which claims priority to JPApplication No. 2010-168164, filed Jul. 27, 2010. The entire disclosuresof all of these applications are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a storage system group including ascale-out storage system configured by a plurality of storage systems,and a management method therefor.

BACKGROUND ART

As business activities come to rely more and more on informationsystems, losses associated with system shutdowns are becoming enormous.As a result of this, greater importance is being attached totechnologies that do not shut down a system or rapidly restore a systemwhen deficiencies such as a system failure or damage occur.

For example, storage cluster technology is disclosed in PatentLiterature 1. In storage cluster technology, data in a first logicalvolume of a first storage system is copied to a second logical volume ofa second storage system. In a case where a failure occurs in the firststorage system, a host computer is able to access the data in the secondlogical volume of the second storage system by switching from an accesspath to the first logical volume to an access path to the second logicalvolume. Furthermore, in the following explanation, a combination of thelogical volume that is the data copy source (copy source volume) and thelogical volume that becomes the data copy destination (copy destinationvolume) will be called a “remote copy pair”.

Also, in Patent Literature 2, disaster recovery technology for rapidlyrestoring a system in a case where the entire system at a site shutsdown due to a disaster or the like is disclosed. According to thedisaster recovery technology, a remote copy pair comprising a firstlogical volume of a first storage system and a second logical volume ofa second storage system, which is used when the first storage system isunable to be used, is configured. This enables the second storage systemto continue operating even when the first storage system has beendamaged. Furthermore, in the following explanation, a first storagesystem that is run during normal operations may be called a “primarystorage system”, and a second storage system that is used in place ofthe first storage system may be called a “secondary storage system”.

CITATION LIST Patent Literature

[PTL 1]

-   Japanese Patent Application Laid-Open No. 2009-32014    [PTL 2]-   Japanese Patent Application Laid-Open No. 2005-18506

SUMMARY OF INVENTION Technical Problem

A scale-out storage system comprising multiple storage systems (will becalled a “virtual storage system” hereinafter) is known. In accordancewith a virtual storage system, the capacity of the virtual storagesystem-provided resource can be flexibly expanded by replenishing thestorage system.

The joining together of remote copy pairs of storage systems in the samevirtual storage system will be considered here. Specifically, forexample, it is supposed that the following environment exists.

-   -   One virtual storage system comprises a first storage system and        a second storage system.    -   There is a first and a second remote copy pair.    -   Copy source volumes and copy destination volumes are mixed        together in both the first and the second storage systems.        Specifically, for example, a first remote copy pair is        configured in a first copy source volume and a first copy        destination volume, and a second remote copy pair is configured        in a second copy source volume and a second copy destination        volume. The first storage system comprises the first copy source        volume and the second copy destination volume. The second        storage system comprises the first copy destination volume and        the second copy source volume.    -   A single consistency group is configured using the first and the        second remote copy pairs. Specifically, the write sequence        (update sequence) of the write data to the first and the second        copy source volumes and the replication sequence (reflection        sequence) of the write data to the first and the second copy        destination volumes are the same.

When the first storage system is damaged in an environment like this, anoperation that uses the first and the second copy source volumes isswitched over to an operation that uses the first and the second copydestination volumes.

However, since the second copy destination volume is in the damagedfirst storage system, it is not possible to restore the data in thesecond copy destination volume.

The user must configure the remote copy pair such that a problem likethis does not occur. For this reason, the user must carry out managementwhile being aware of the corresponding relationship between the virtualstorage system and the storage systems that comprise same. This is aburden on the user.

Therefore, an object of the present invention is to lessen themanagement burden on the user who manages a storage group including ascale-out storage system.

Solution to Problem

A management system is coupled to a storage system group comprising avirtual storage system, which is a scale-out storage system comprisingmultiple storage systems. The management system comprises storagemanagement information comprising information that denotes whether ornot a storage system is a component of the virtual storage system foreach storage system. The management system, based on the storagemanagement information, determines whether or not a first storage systemis a component of the virtual storage system, and in a case where theresult of this determination is affirmative, identifies on the basis ofthe storage management information a second storage system, which is astorage system other than the virtual storage system comprising thefirst storage system, and only allows the user to perform a specificoperation with respect to this second storage system.

Advantageous Effects of Invention

It is possible to manage a virtual storage system comprising multiplestorage systems by treating it as a single storage system. This makes itpossible to lessen the management burden on the user, who manages thestorage system group including the scale-out storage system.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing an example of a computer system of a firstexample.

FIG. 2 is a diagram showing an example of the configuration of either aprimary or a secondary storage system of the first example.

FIG. 3 is a diagram showing an example of the configuration of amanagement computer of the first example.

FIG. 4 is a diagram showing an example of the configuration of either aprimary or a secondary host computer of the first example.

FIG. 5 is a diagram showing an overview of a scale-out storage system ofthe first example.

FIG. 6 is a diagram showing one example of the configuration of astorage and a remote copy of the first example.

FIG. 7 is a diagram showing an example of the configuration of a volumemanagement table of the first example.

FIG. 8 is a diagram showing an example of the configuration of a volumeset representative management table of the first example.

FIG. 9 is a diagram showing an example of the configuration of a volumeset management table of the first example.

FIG. 10 is a diagram showing an example of the configuration of a copypair management table of the first example.

FIG. 11 is a diagram showing an example of the configuration of a writedata management table of the first example.

FIG. 12 is a diagram showing an example of the configuration of astorage management table of the first example.

FIG. 13 is a diagram showing an example of the configuration of a volumeconsolidation management table of the first example.

FIG. 14 is a diagram showing an example of the configuration of a volumeset consolidation management table of the first example.

FIG. 15 is a flowchart of a write request process of the first example.

FIG. 16 is a flowchart of a write date transfer process of the firstexample.

FIG. 17 is a flowchart of a write data reflection process performed by arepresentative storage system of the first example.

FIG. 18 is a flowchart of a write data reflection process performed by anon-representative storage system of the first example.

FIG. 19 is a flowchart of a virtual volume set creation process of thefirst example.

FIG. 20 is a diagram showing a virtual volume creation screen providedby a storage management program of the first example.

FIG. 21 is a flowchart showing one portion of a remote copy paircreation process of the first example.

FIG. 22 is a flowchart showing another portion of the remote copy paircreation process of the first example.

FIG. 23 is a flowchart showing the remainder of the remote copy paircreation process sequence of the first example.

FIG. 24 is a diagram showing a remote copy pair creation screen providedby the storage management program of the first example.

FIG. 25 is a flowchart of a storage addition process of the firstexample.

FIG. 26 is a diagram showing a storage addition screen of the firstexample.

FIG. 27 is a flowchart of failover requirement determination process ofthe first example.

FIG. 28 is a diagram of the configuration of a computer system of asecond example.

FIG. 29 is a diagram showing an example of the configuration of astand-alone management computer of the second example.

FIG. 30 is a flowchart of a configuration error determination process ofthe second example.

FIG. 31 is a diagram showing an example of the configuration of astorage system for which a failover is not required in the firstexample.

DESCRIPTION OF EMBODIMENT

A management computer of a scale-out storage apparatus related to anembodiment of the present invention will be explained below by using thedrawings.

In the following explanation, various types of information will beexplained using the expression “xxx table”, but these various types ofinformation may be expressed using a data structure other than a table.To show that the information is not dependent on the data structure,“xxx table” may be called “xxx information”.

Further, an ID (identifier) will be used for identifying an element inthe following explanation, and a name, a number, or the like may be usedas the ID.

In the following explanation, a “program” may be used as the subject inexplaining a process, but since a prescribed process is performed inaccordance with a program being executed by a processor (for example, aCPU (Central Processing Unit)) while using a storage resource (forexample, a memory) and/or a communication interface device (for example,a communication port) as needed, the subject of the processing may alsobe the processor. A process that is explained with a program as thesubject may be a process that is performed by the management system. Theprocessor may comprise a hardware circuit that processes either all or aportion of a process performed by the processor. A computer program maybe installed in respective computers from a program source. The programsource, for example, may be a program delivery server or a storagemedium.

The management system may comprise one or more computers. Specifically,for example, in a case where the management computer either displaysinformation or sends display information to a remote computer, themanagement computer is a management system. Furthermore, for example, ina case where the same functions as those of the management computer arerealized using multiple computers, the relevant multiple computers (mayinclude a display computer in a case where a display computer performs adisplay) are the management system.

Example 1

FIG. 1 is a diagram showing an example of the configuration of acomputer system of a first example.

A computer system 1 comprises a primary storage system 10 a, a secondarystorage system 10 b, a management computer 20, a primary host computer30 a, a secondary host computer 30 b, a management network 40, and astorage network 50.

The primary host computer 30 a and the primary storage system 10 a arecoupled together via the storage network 50. Similarly, the secondaryhost computer 30 b and the secondary storage system 10 b are alsocoupled together via the storage network 50. Furthermore, the primarystorage system 10 a and the secondary storage system 10 b are alsocoupled together via the storage network 50.

The primary host computer 30 a, the primary storage system 10 a, thesecondary host computer 30 b, and the secondary storage system 10 b arecoupled to the management computer 20 via the management network 40.

Furthermore, in the example of FIG. 1, multiple primary host computers30 a and secondary host computers 30 b are shown, but there can also beone each. Also in the example of FIG. 1, a single management computer 20is shown, but there may also be multiple management computers 20.

The storage network 50 is a network system used primarily forcommunications based on an IO (Input/Output) request carried out betweenthe primary host computer 30 a and the primary storage system 10 a, andcommunications based on an IO request carried out between the secondaryhost computer 30 b and the secondary storage system 10 b. Furthermore,the storage network 50 is also used for remote copy-based communicationsbetween the primary storage system 10 a and the secondary storage system10 b.

For example, either a LAN (Local Area Network) or a SAN (Storage AreaNetwork) may be used as the storage network 50. The storage network 50may be comprised of a network switch and a hub. In this example, thestorage network 50 is a fibre channel protocol-based SAN (FC (FibreChannel)-SAN).

The management network 40 is used when the management computer 20 ismanaging the primary host computer 30 a, the primary storage system 10a, the secondary host computer 30 b, and the secondary storage system 10b. In this example, the management network 40 is an IP (InternetProtocol)-based LAN. However, this does not negate the fact that thestorage network 50 and the management network 40 can be formed on asingle network. For example, in a case where the storage network 50comprises an IP protocol-based network, the storage network 50 and themanagement network 40 can also be formed on a single network system.

FIG. 2 is a diagram showing an example of the configuration of either aprimary or a secondary storage system of the first example.

Since the configuration of the secondary storage system 10 b ispractically identical to that of the primary storage system 10 a, anexplanation of the former will be omitted.

However, different roles are allocated to the primary storage system 10a and the secondary storage system 10 b from the standpoint ofoperations. That is, the primary storage system 10 a is the storagesystem that is run during normal operations. Alternatively, thesecondary storage system 10 b stores a replication of the data of theprimary storage system 10 a, and is operated as an alternative systemwhen the storage system 10 a is unable to be used due to a disaster,maintenance, or the like.

The primary storage system 10 a comprises a controller 110 and a diskapparatus 120.

The disk apparatus 120 stores data in accordance with a write requestfrom the primary host computer 30 a. The disk apparatus 120 is adisk-type physical storage device (for example, a HDD (Hard DiskDrive)). Another physical storage device (for example, a flash memorydevice) may also be used as the physical storage device.

The controller 110 controls the primary storage system 10 a in itsentirety. For example, the controller 110 writes data to the diskapparatus 120, reads data from the disk apparatus 120, and controls aremote copy from the primary storage system 10 a to the secondarystorage system 10 b.

The controller 110 also provides a storage area of the disk apparatus120 to the primary host computer 30 a as one or more logical volume 121.As shown in the drawing, there may be multiple disk apparatuses 120.Furthermore, the controller 110 may use RAID (Redundant Arrays ofIndependence Disks) technology, and may comprise multiple logicalvolumes 121 based on multiple disk apparatuses 120. Hereinafter, alogical volume 121 may simply be called a “volume”.

The controller 110, as shown in the drawing, comprises a processor (forexample, a CPU (Central Processing Unit)) 111, a memory (hereinaftercontrol memory) 112, a cache memory 113, a data interface (data IF) 114,a disk interface (disk IF) 115, and a management interface (managementIF) 116.

These components (111, 112, 113, 114, 115 and 116) are coupled togethervia an internal network 117. These respective components may be duplexedby using a redundant configuration.

The processor 111 performs various processes in accordance withexecuting a control program 1126 that is stored in the control memory112.

In addition to the above-mentioned control program 1126, tables that theprocessor 111 needs when executing the control program 1126 are alsostored in the control memory 112.

Specifically, for example, the control memory 112 stores a volumemanagement table 1121, a volume set management table 1123, a copy pairmanagement table 1124, and a write data management table 1125.

Furthermore, a volume set representative management table 1122 is storedin a storage system defined as the representative storage of a group.Hereinbelow, the storage system defined as the group representativestorage will be called the “representative storage system”. Only one ofthe storage systems included in the virtual storage system is registeredas the representative storage system.

In a storage system that is not a virtual storage system, this storagesystem is registered as being the representative storage system.Furthermore, the respective tables provided by the primary storagesystem 10 a will be described further below.

The control program 1126 is for controlling the entire primary storagesystem 10 a, and processes an IO request from the primary host computer30 a, a remote copy, and a storage management request from themanagement computer 20.

The cache memory 113 temporarily stores data that is to be written tothe disk apparatus 120 and data read from the disk apparatus 120 (actualdata, and write/read time management information).

The data interface 114 is for carrying out communications between theprimary host computer 30 a and the primary storage system 10 a, whichare coupled via the storage network 50.

Specifically, the data interface 114 is used when receiving an IOrequest (for example, a read request or a write request) from theprimary host computer 30 a, and sending data, which has been read fromthe disk apparatus 120, to the host computer 30 a. This interface 114 isalso used for carrying out communications between the storage systemsthat comprise the same virtual storage system. In addition, the datainterface 114 is also used when sending and receiving the data exchangedbetween the primary storage system 10 a and the secondary storage system10 b when carrying out a remote copy.

The disk interface 115 is used for carrying out communications betweenthe disk apparatus 120 (the apparatus coupled via the internal network117) and the cache memory 113. The disk interface 115, for example,enables the control program 1126 to fetch data stored in the cachememory 113 and store same in the disk apparatus 120, and to read datafrom the disk apparatus 120 and write same to the cache memory 113.

The primary storage system 10 a uses the management interface 116 whencarrying out communications with the management computer 20 (thecomputer coupled via the management network 40). The managementinterface 116 is used when the control program 1126 receives aninstruction from the management computer 20, and sends primary storagesystem 10 a table information to the management computer 20.

FIG. 3 is a diagram showing an example of the configuration of amanagement computer of the first example.

The management computer 20 is for managing the primary storage system 10a and the secondary storage system 10 b. The management computer 20comprises a memory 210, a processor (for example, a CPU) 220, and amanagement interface 230. The memory 210, the processor 220, and themanagement interface 230 are coupled together via an internal networkthat has been omitted from the drawing.

The processor 220 performs various processing by executing a programstored in the memory 210.

The memory 210 stores a storage management table 2101, a volumeconsolidation management table 2102, a volume set consolidationmanagement table 2103, a storage management program 2104, and an OS(Operating System) 2105.

The storage management table 2101, the volume consolidation managementtable 2102, and the volume set consolidation management table 2103 areused by the storage management program 2104 that is executed by theprocessor 220. Each table will be explained in detail further below.

The storage management program 2104 provides the user with a userinterface for managing the primary storage system 10 a and the secondarystorage system 10 b. Furthermore, the storage management program 2104performs management (for example, a setting, an execution instruction,and monitoring of the operational status) with respect to the primarystorage system 10 a and the secondary storage system 10 b based on auser operation. For example, the storage management program 2104provides a user interface, receives an instruction, such as constructremote copy environment and operate on copy pair, from the user via thisuser interface, and sends this instruction to the primary storage system10 a and the secondary storage system 10 b.

The OS 2105 is a program for controlling all of the processing performedby the management computer 20.

Furthermore, the management computer 20 may comprise a display deviceand an input device that are not shown in the drawing. The displaydevice, for example, is a liquid crystal display device, and the inputdevice, for example, is either a keyboard or a mouse. The managementcomputer 20 may also comprise an apparatus that integrates the displaydevice and the input device (for example, a touch panel-type displayapparatus). In the following explanation, it is supposed that a screenand other such information will be displayed on the display device, andthat the user will use the input device to perform a desired operation.

FIG. 4 is a diagram showing an example of the configuration of either aprimary or a secondary host computer of the first example.

Since the secondary host computer 30 b has the same configuration as theprimary host computer 30 a, an explanation thereof will be omitted.

However, different roles are allocated to the primary host computer 30 aand the secondary host computer 30 b from the operational standpoint.The primary host computer 30 a operates during normal operations, andthe secondary host computer 30 b is used as an alternative system whenthe primary host computer 30 a is unable to be used due to a disaster,maintenance, or the like.

The primary host computer 30 a, for example, forms the core of aprescribed business system (for example, a banking business system or anairline seat reservation business system). The primary host computer 30a comprises a memory 310, a processor 320, a data interface 330, and amanagement interface 340. The memory 310, the processor 320, the datainterface 330, and the management interface 340 are coupled together viaan internal network that has been omitted from the drawing.

The memory 310 stores an application 3101, a path management program3102, and an OS 3103.

The application 3101 and the path management program 3102 are executedby the processor 320.

The application 3101, for example, is a program for managing a database,and based on the data stored in the volume 121, performs a data write tothe volume 121 or a data read from the volume 121.

The path management program 3102 selectively switches the path for theprimary host computer 30 a to access data disposed in the primarystorage system 10 a. In a case where multiple paths for accessing thedata are registered, when one path is unable to be used due to a failureor the like, the data can be accessed using another path.

The OS 3103 is a program for controlling all of the processing performedby the primary host computer 30 a.

Next, an overview of a scale-out storage system will be explained.

A scale-out storage system is a single virtual storage system in whichmultiple storage systems are interlinked. The configuration of ascale-out storage system can be made larger or smaller by adjusting thenumber of interlinked storage systems.

FIG. 5 is a diagram showing an overview of a scale-out storage system ofthe first example.

A primary storage system A (10 a) described in FIG. 5 is a scale-outstorage system, and comprises two storage systems, i.e. primary storagesystem D and primary storage system E.

According to this drawing, the primary storage system D comprises anactual volume D1. The actual volume D1 is associated with a virtualvolume E1 of the primary storage system E. Furthermore, the primarystorage system E comprises an actual volume E3. The actual volume E3 isassociated with a virtual volume D3 of the primary storage system D. Theactual volumes D1 and E3 and the virtual volumes E1 and D3 arerespectively allocated by the primary host computer 30 a. An “actualvolume” is either all or a portion of the storage space of one or moredisk apparatuses 120 (for example, a RAID group). A “virtual volume” isa virtual logical volume that is not based on the disk apparatus 120.

Next, an overview of the processing performed when the primary storagesystem A receives an IO request from the primary host computer 30 a withrespect to a volume will be explained.

In general, when a primary storage system receives an IO request (eithera write request or a read request) with respect to a volume from aprimary host computer, the primary storage system determines whetherthis request is an IO request with respect to an actual volume or an IOrequest with respect to a virtual volume. In the case of an IO requestwith respect to an actual volume, the primary storage system performsthe IO of the data to the I/O destination actual volume and ends theprocessing. Alternatively, in the case of an IO request with respect toa virtual volume, the primary storage system identifies the actualvolume that is associated with the I/O destination virtual volume, andtransfers the IO request with respect to the identified actual volume tothe storage system that comprises this actual volume.

A specific explanation will be given using the configuration of FIG. 5as an example. In a case where the primary storage system E receives awrite request from the primary host computer 30 a with respect to thevirtual volume E1, the primary storage system E executes a write to theactual volume D1 by way of the virtual volume E1. Similarly, in a casewhere the primary storage system E receives a read request from theprimary host computer 30 a with respect to the virtual volume E1, theprimary storage system E reads the data from the actual volume D1, andsends the read data to the primary host computer 30 a by way of thevirtual volume E1.

By contrast, in a case where the primary storage system D receives awrite request with respect to the actual volume D1 directly from theprimary host computer 30 a (without going through the virtual volumeE1), the primary storage system D writes the data to the actual volumeD1. Similarly, in a case where the primary storage system D receives aread request with respect to the actual volume D1 directly from theprimary host computer 30 a (without going through the virtual volumeE1), the primary storage system D reads the data from the actual volumeD1, and sends the read data to the host computer 30 a.

That is, the primary host computer 30 a has two paths via which toaccess the respective actual volumes D1 (E3), a path for directlyaccessing the respective actual volumes D1 (E3), and a path foraccessing the respective actual volumes D1 (E3) by way of the associatedvirtual volumes E1 (D3). The path management program 3102 disposed inthe primary host computer 30 a selectively switches these paths toaccess the actual volume D1 (E3). With a configuration like this, sincethe primary host computer 30 a is able to select either the path thatdirectly accesses the actual volume D1 (E3) or the path that access theactual volume D1 (E3) by way of the virtual volume E1 (D3), even if onepath fails, the system is able to continue to operate provided the otherpath does not fail. Furthermore, as seen from the perspective of primaryhost computer 30 a, the primary storage system D and the primary storagesystem E can be viewed as the single virtual storage system A.

Next, an overview of a remote copy carried out between a primary storagesystem and a secondary storage system will be explained.

A remote copy is the replication of the data of a primary storage systemin a secondary storage system so that operations will be able tocontinue using the secondary storage system even if a failure,maintenance or the like makes it impossible to use the primary storagesystem.

A remote copy is realized in accordance with the following operations.

-   -   An “initial copy” via which all the data stored in the volume of        the primary storage system is replicated in the volume of the        secondary storage system.    -   An “update copy” via which, in a case where a write request is        generated with respect to the volume of the primary storage        system, the write data (the data according to this write        request) is transferred to the secondary storage system E and        the volume of the secondary storage system E is updated in        accordance with the transferred write data.

Furthermore, a volume pair (a combination of a copy source volume and acopy destination volume) for a remote copy will be called a “remote copypair” in this example.

In this example, a group comprising one or more copy source volumesincluded in one or more remote copy pairs may be called either a “copysource volume set” or simply a “volume set”, and a group comprising oneor more copy destination volumes included in one or more remote copypairs may be called either a “copy destination volume set” or simply a“volume set”.

The sequence in which write data is updated to one or more copy sourcevolumes in a copy source volume set is the same as the sequence in whichthe write data is reflected in the one or more copy destination volumesin the copy destination volume set corresponding to this copy sourcevolume set.

The multiple copy source volumes in one copy source volume set mayreside in different multiple storage systems. Similarly, the multiplecopy destination volumes in one copy destination volume set may residein different multiple storage systems.

However, in a case where a failure occurs in a primary storage system(for example, in a certain volume) and the primary storage system thatis currently operating can no longer be used, the host computer 30 aperforms an operation for switching the access destination from theprimary storage system to a normal secondary storage system. However,the problem is that the system will no longer be able to operate in acase where the switch-destination secondary storage system also has afailed volume. Therefore, as shown in the example of FIG. 6, whencreating a remote copy pair, it is necessary to combine actual volumesthat are not components of the same virtual storage system.

FIG. 6 is a diagram showing an example of a storage configuration and aremote copy pair configuration of the first example.

This drawing comprises a primary storage system A and a secondarystorage system C.

The primary storage system A is a scale-out storage system. The primarystorage system A comprises a primary storage system D and a primarystorage system E. A primary storage system B is not a scale-out storagesystem. The secondary storage system C is a scale-out storage system.The secondary storage system C comprises a secondary storage system Fand a secondary storage system G.

Actual volumes D1 and D2 of the primary storage system D arerespectively associated with virtual volumes E1 and E2 of the primarystorage system E. In addition, an actual volume E3 of the primarystorage system E is associated with a virtual volume D3 of the primarystorage system D.

A volume set A (set A) resides in the primary storage system A. Thevolume set A (set A) comprises a volume set D (set D) of the primarystorage system D and a volume set E (set E) of the primary storagesystem E. A volume set B (set B) also exists in the primary storagesystem B.

A volume set C (set C) exists in the secondary storage system C. Thevolume set C (set C) comprises a volume set F (set F) of the secondarystorage system F and a volume set G (set G) of the secondary storagesystem G.

A volume D1 and a volume D2 exist in the volume set D. The volume D1 anda volume F1, which belongs to the volume set F, form one remote copypair, and the volume D2 and a volume F2, which belongs to the volume setF, form another remote copy pair.

In addition, a volume E3 exists in the volume set E. The volume E3 and avolume G1, which belongs to the volume set G, form a remote copy pair.

Actual volumes D1, D2 and E3 belong to volume set A (set A) and formremote copy pairs with actual volumes F1, F2 and G1 that belong tovolume set C (set C). For this reason, the write data update sequence(write sequence) with respect to the volumes D1, D2 and E3 is the sameas the write data reflection sequence (write sequence) with respect tothe volumes F1, F2 and G1. For example, in a case where data is writtenin the order D1→D2→E3 to the actual volumes D1, D2 and E3 of the primarystorage system. A, the data is written in the order F1→F2→G1 on thesecondary storage system C side.

FIG. 7 is a diagram showing an example of the configuration of a volumemanagement table of the first example.

The volume management table 1121 is used by the control program 1126(refer to FIG. 2) to manage the volume(s) of the primary storage system10 a. There is also a volume management table 1121 in the secondarystorage system 10 b, but since the configurations are practically thesame, the volume management table 1121 of the primary storage system 10a will be explained below.

The volume management table 1121 comprises a volume ID 11211, a volumetype 11212, an actual storage ID 11213, an actual volume ID 11214, acapacity 11215, and a pair ID 11216 for each volume.

The volume ID 11211 is an ID used by the control program 1126 touniquely identify a volume of the primary storage system 10 a.

The volume type 11212 is information denoting the type of the volume(for example, a volume is either a virtual volume or an actual volume)identified from the volume ID 11211. The volume type 11212 is “virtual”when the volume is a virtual volume, and is “actual” when the volume isan actual volume.

The actual storage ID 11213 and the actual volume ID 11214 areinformation that is registered in a case where the volume type 11212 is“virtual”. In a case where the volume type 11212 is “virtual”, theactual volume ID 11214 is the ID of the actual volume associated withthe virtual volume. Furthermore, the actual storage ID 11213 is (the IDof) the actual storage system that comprises the actual volume (theactual volume associated with the virtual volume) identified from theactual volume ID 11214. The “actual storage system” is a storage systemthat is not a virtual storage system, and specifically, is either astorage system that is included in a virtual storage system, or astorage system that is not included in the virtual storage system.

In a case where the volume type 11212 is “actual”, the actual storage ID11213 and the actual volume ID 11214, for example, are invalid values(for example, “N/A”).

The capacity 11215 is information denoting the capacity of the volumeidentified from the volume ID 11211.

The pair ID 11216 is the ID of the remote copy pair comprising thevolume that is identified from the volume ID 11211. In a case where thisvolume is not included in the remote copy pair, the pair ID 11216, forexample, is an invalid value (for example, “N/A”).

FIG. 8 is a diagram showing an example of the configuration of a volumeset representative management table of the first example.

The volume set representative management table 1122 is used by thecontrol program 1126 (see FIG. 2) to manage a virtual volume setcomprising multiple volume sets. The volume set representativemanagement table 1122 exists only in the representative storage system.The control program 1126, based on the volume set representativemanagement table 1122, is able to collectively manage volume setscomprising the volume sets of multiple storage systems.

In the example of FIG. 6, the volume set representative management table1122, which is disposed in the representative storage system inside theprimary storage system A, comprises information related to the volumeset A (set A). The volume set representative management table 1122,which is disposed in the representative storage system inside thesecondary storage system C, comprises information related to the volumeset C (set C).

The volume set representative management table 1122 comprises a volumeset ID 11221, a container time 11222, a number of volume sets 11223, anactual volume set ID 11224, and an actual storage ID 11225 for eachvirtual volume set. The virtual volume set is a virtual volume setcomprising multiple volume sets. The virtual volume set, for example, isa consistency group (a group in which the consistency of the data ismaintained), and, specifically, for example, comprises one or more copysource volume sets and one or more copy destination volume setscorresponding thereto.

The volume set ID 11221 is an ID used by the control program 1126 touniquely identify a virtual volume set.

The container time 11222 is information denoting the time at which theprocessor 111 last wrote data to either of the volumes comprising thevirtual volume set (the volume set identified from the volume set ID11221). The container time 11222 is only registered in therepresentative management table 1122 of the secondary storage systemside.

The number of volume sets 11223 is information denoting the total numberof volume sets that comprise the virtual volume set identified by thevolume set ID 11221.

The actual volume set ID 11224 is the ID of the actual volume set thatcomprises the virtual volume set identified from the volume set ID11221. The “actual volume set” is the volume set that is not the virtualvolume set, and, specifically, is the volume set comprising the virtualvolume set.

The actual storage ID 11225 is the ID of the storage system comprisingthe volume set identified from the actual volume set ID 11224.

The total number of actual volume set IDs 11224 (actual storage IDs11225) is the same as the number denoting the number of volume sets11223.

FIG. 9 is a diagram showing an example of the configuration of a volumeset management table of the first example.

The volume set management table 1123 resides in the primary storagesystem 10 a and in the secondary storage system 10 b. The volume setmanagement table 1123 is used by the control program 1126 to manage thevolume sets of the primary storage system 10 a and the secondary storagesystem 10 b. The configuration of the volume set management table 1123is the same in both the primary storage system 10 a and the secondarystorage system 10 b, and as such, the following explanation will focuson the configuration of the volume set management table 1123 of theprimary storage system 10 a (the secondary storage system 10 b will beexplained as needed).

The volume set management table 1123 comprises a volume set ID 11231, anumber of volumes 11232, a volume ID 11233, a partner storage ID 11234,a partner volume set ID 11235, and a latest data reflection time 11236for each volume set.

The volume set ID 11231 is the ID used by the control program 1126 touniquely identify the volume set of the primary storage system 10 a.

The number of volumes 11232 is information denoting the total number ofvolumes comprising the volume set (the volume set identified from thevolume set ID 11231).

The volume ID 11233 is the ID of the volume included in the volume set(the volume set identified from the volume set ID 11231). The number ofIDs registered as the volume ID 11233 is equivalent to the numberdenoted by the number of volumes 11232.

The partner storage ID 11234 is the ID of a secondary storage systemthat constitutes the remote copy destination of a primary storagesystem.

The partner volume set ID 11235 is the ID for identifying the volume set(the volume set of the storage system identified by the partner storageID 11234), which is the remote copy destination.

The latest data reflection time 11236 is information showing the time atwhich the processor 111 last wrote data to the volume that belongs tothe remote copy destination volume set. The latest data reflection time11236 is only registered in the volume set management table 1123 of thesecondary storage system.

FIG. 10 is a diagram showing an example of the configuration of a copypair management table of the first example.

The copy pair management table 1124 is used by the control program 1126to manage the remote copy pair relationship between the volume of theprimary storage system 10 a and the volume of the secondary storagesystem 10 b. The same table is also in the secondary storage system 10b.

The copy pair management table 1124 comprises a pair ID 11241, a volumeID 11242, a volume set ID 11243, a partner storage ID 11244, and apartner volume ID 11245 for each remote copy pair.

The pair ID 11241 is the ID used by the control program 1126 to uniquelyidentify the remote copy pair.

The volume ID 11242 is the ID used by the control program 1126 touniquely identify the copy source volume that belongs to the primarystorage system.

The volume set ID 11243 is the ID of the volume set to which the volumeidentified from the volume ID 11242 belongs.

The partner storage ID 11244 is the ID of the remote copy destinationstorage system of the volume identified from the volume ID 11242.

The partner volume ID 11245 is the ID of the remote copy destinationvolume (the volume of the storage system identified from the partnerstorage ID 11244) of the volume identified from the volume ID 11242.

FIG. 11 is a diagram showing an example of a write data management tableof the first example.

The write data management table 1125 is used by the control program 1126(refer to FIG. 2) to manage information for transferring and reflectingthe write data stored in the copy source volume to the copy destinationvolume.

The write data management table 1125 comprises a volume ID 11251, awrite destination address 11252, a write data length 11253, a write datacache pointer 11254, a sequential number 11255, a write time 11256, anda remote copy requirement 11257 for each write data.

The volume ID 11251 is the ID used by the control program 1126 touniquely identify a write destination volume.

The write destination address 11252 is the address of the write datawrite destination area (a storage area in the write destination volume).

The write data length 11253 is information denoting the data size of therelevant write data.

The write data cache pointer 11254 denotes the cache area in which thewrite data is to be stored temporarily.

The sequential number 11255 is a number (a sequential number) denotingthe sequence in which data has been written to a volume belonging to thevolume set. For example, in a case where a single storage systemcomprises a first and a second copy source volume set (a set of one ormore copy source volumes), there is a separate sequential number foreach copy source volume set. Furthermore, in a case where the multiplecopy source volumes included in one copy source volume set are inmultiple storage systems, for example, the sequential numbercorresponding to the relevant copy source volume set is used no matterwhich of these multiple copy source volumes the write data is writtento.

The write time 11256 is information denoting the write time of therelevant write data. Furthermore, the write time may be the time (forexample, the time denoted by a time stamp of a write request) capable ofbeing acquired from the write data-related management information senttogether with the write data from the host computer 30 a, may be thetime at which the write request was received, or may be the time atwhich the write data was written to the write destination volume (thevolume identified from the write request) in accordance with the writerequest.

The remote copy requirement 11257 is an identifier denoting the presenceor absence of a remote copy target. In a case where a remote copy isneeded, the remote copy requirement 11257 is “required”, and in a casewhere a remote copy is not needed, the remote copy requirement 11257 is“not required”.

FIG. 12 is a diagram showing an example of the configuration of astorage management table of the first example.

The storage management table 2101 is used by the processor 220 (refer toFIG. 3) to manage a storage system that is managed by the storagemanagement program 2104, and the scale-out configuration of each storagesystem.

The storage management table 2101 comprises a storage ID 2101, ascale-out availability 21012, an actual storage ID 21013, and arepresentative storage ID 21014.

The storage ID 21011 is an ID for uniquely identifying a storage systemthat is managed by the storage management program 2104. In the case of astorage system that is a virtual storage system comprising multiplestorage systems, the storage ID 21011 is the ID of the virtual storagesystem.

The scale-out availability 21012 is an identifier denoting whether ornot the storage system identified from the storage ID 21011 is a storagesystem that is capable of scale-out. In a case where the storage systemis a scale-out-enabled storage (a virtual storage system), the scale-outavailability 21012 is “ON”. Alternatively, in a case where the storagesystem is not a scale-out storage system, the scale-out availability21012 is “OFF”.

The actual storage ID 21013 registers the ID of the storage systemcomprising the storage system identified from the storage ID 21011. In acase where the storage system is not a scale-out storage, the actualstorage ID 21013 is the same ID as the storage ID 21011.

The representative storage ID 21014 is the ID of the storage system thatis the representative of one or more storage systems corresponding toone or more IDs registered in the actual storage ID 21013.

According to the example of FIG. 12, a storage system “Storage A” is avirtual storage system comprising a storage system “Storage D” and astorage system “Storage E”. The representative storage system in thisvirtual storage system is the storage system “Storage D”.

FIG. 13 is a diagram showing an example of the configuration of a volumeconsolidation management table of the first example.

The volume consolidation management table 2102 is for managing a volume(the volume managed by the storage management program 2104) of thestorage system. The volume consolidation management table 2102 iscreated based on the storage management table 2101 and the volumemanagement table 1121 (the table 1121 disposed in each storage system).

The volume consolidation management table 2102 comprises a volume ID21021, a storage ID 21022, a scale-out availability 21023, an actualstorage ID 21024, a volume type 21025, an actual volume ID 21026, and anactual storage ID 21027 for each volume.

The volume ID 21021 is an ID used by the storage management program 2104to uniquely identify a volume. The volume ID 21021 is the ID acquiredwith respect to each storage system from the volume management table1121 held by each storage system.

The storage ID 21022 is the ID of the storage system comprising thevolume identified from the volume ID 21021.

The scale-out availability 21023 is an identifier denoting whether ornot the storage system identified from the storage ID 21022 is ascale-out-enabled storage system.

The actual storage ID 21024 is the ID of the storage system thatactually comprises the volume identified from the volume ID 21021 andthe storage ID 21022.

The volume type 21025, the actual volume ID 21026, and the actualstorage ID 21027 are information registered in a case where theidentifier registered in the scale-out availability 21023 is “ON”.

The volume type 21025 is information denoting the type of volume(whether the volume is a virtual volume or an actual volume) that wasidentified from the IDs registered in the volume ID 21021 and thestorage ID 21022.

The actual volume ID 21026 and the actual storage ID 21027 areinformation registered in a case where the volume type 21025 is“virtual”.

The actual volume ID 21026 is the ID of the actual volume that isassociated with the virtual volume identified from the volume ID 21021.

The actual storage ID 21027 is the ID of the storage system comprisingthe actual volume identified from the actual volume ID 21026.

According to the example of FIG. 13, a volume “VOL D3” is the volume ofa storage system “Storage A”. Furthermore, the storage system “StorageA” is a scale-out storage system, and the volume “VOL D3” actuallyresides in a storage system “Storage D”. In addition, this volume “VOLD3” is a virtual volume, and an actual volume “VOL E3” of a storagesystem “Storage E” is associated with this virtual volume.

FIG. 14 is a diagram showing an example of the configuration of a volumeset consolidation management table of the first example.

The volume set consolidation management table 2103 is used by theprocessor 220 to manage a volume set (the volume set managed by thestorage management program 2104) of a storage system. The volume setconsolidation management table 2103 is created based on information ofthe table 1122 of the representative storage system, and information ofthe table 1123 of each storage system.

The volume set consolidation management table 2103 comprises a volumeset ID 21031, a storage ID 21032, a partner volume set ID 21033, apartner storage ID 21034, a volume set type 21035, a configurationvolume set ID 21036, a configuration status 21037, and a virtual volumeset ID 21038 for each volume set.

The volume set ID 21031 is an ID used by the storage management program2104 to uniquely identify a volume set.

The storage ID 21032 is the ID of the storage system comprising thevolume set identified from the volume set ID 21031.

The partner volume set ID 21033 is the ID of the volume set, which isthe remote copy destination of the volume set identified from the volumeset ID 21031.

The partner storage ID 21034 is the ID for identifying the storagesystem comprising the volume set identified from the partner volume setID 21033. Furthermore, in a case where a remote copy pair has yet to beformed, the partner volume set ID 21033 and the partner storage ID 21034are both “unregistered”.

The volume set type 21035 is information denoting the type of the volumeset identified from the volume set ID 21031. In a case where the volumeset is a virtual volume set, the volume set type 21035 is “virtual”, andin a case where the volume set is an actual volume set, the volume settype 21035 is “actual”.

The configuration volume set ID 21036 is the ID of the volume setincluded in the volume set (that is, the virtual volume set), for whichthe volume set type 21035 is “virtual”.

The configuration status 21037 is an identifier denoting whether or notthe volume set, for which the volume set type 21035 is “actual”, is thevolume set included in the actual volume set. In a case where the volumeset is the volume set included in the virtual volume set, theconfiguration status 21037 is “ON”, and in a case where it is not, theconfiguration status 21037 is “N/A”.

The virtual volume set ID 21038 is registered with respect to a volumeset for which the volume set type 21035 is “actual” and theconfiguration status 21037 is “ON”. The virtual volume set ID 21038 isthe ID of the virtual volume set that comprises the volume setidentified from the volume set ID 21041.

According to FIG. 14, a volume set “Set A” resides in a storage system“Storage A”. This volume set is associated with a volume set “Set C” ofa storage system “Storage C”.

However, the volume set “Set A” is a virtual volume set. Actually, thevolume set “Set A” comprises a volume set “Set D” (the volume set thatresides in a storage system “Storage D”) and a volume set “Set E” (thevolume set that resides in a storage system “Storage E”). The volume set“Set D” is associated with a volume set “Set F” (the volume set thatresides in a storage system “Storage F”). Furthermore, the volume set“Set E” is associated with a volume set “Set G” (the volume set thatresides in a storage system “Storage G”).

FIG. 15 is a flowchart of a write request process.

Specifically, this drawing shows the flow of a write request process inaccordance with the control program 1126 (refer to FIG. 2) in a casewhere the primary storage system 10 a has received a write request (awrite request with respect to the copy source volume of a remote copy)from the primary host computer 30 a.

The control program 1126, upon receiving the write request from theprimary host computer 30 a (S1501), analyzes this write request. Inaccordance with this, the control program 1126 acquires an ID of thewrite destination volume, a write address, a write data length, writetime information (information denoting the write time) and write data(S1502).

The control program 1126 performs the following processing in S1503:

-   -   acquires the volume type 11212 of the write destination volume        by using the wrote destination volume ID to reference the volume        management table 1121; and    -   determines from the identified volume type 11212 whether or not        the write destination volume is a virtual volume.

In a case where the volume type 11212 of the write destination volume is“virtual” (S1503: Yes), the control program 1126 identifies the actualstorage ID 11213 and the actual volume ID 11214 that are associated withthe write destination virtual volume from the volume management table1121 (that is, identifies the actual volume associated with the writedestination virtual volume, and the actual storage comprising thisactual volume) (S1508).

In addition, the control program 1126 transfers the write request thatspecifies the actual volume identified in S1508 to the actual storagesystem identified in S1508, and ends the write-request-receiveprocessing in the relevant storage system (S1509). Furthermore, thewrite request is processed in the transfer destination storage systemthe same as in the flow of processing of FIG. 15. The write address (theaddress denoting the write destination storage area), which is specifiedin the transferred write request, specifies the address of the actualvolume corresponding to the write address of the virtual volume acquiredin S1502. The virtual volume address and the actual volume address aremanaged in the transfer source storage system.

In a case where the volume type of the write destination volume is not“virtual” (S1503: No), the control program 1126 stores the write dataacquired in S1502 in the cache memory 113 (S1504).

The control program 1126 checks whether a valid pair ID 11216 isregistered in the write destination volume by using the writedestination volume ID to reference the volume management table 1121.That is, the control program 1126 checks whether or not the writedestination volume is the remote copy target (S1505).

In a case where the write destination volume is the remote copy target(S1505: Yes), the control program 1126 associates the write timeinformation acquired in S1502 to the write data (S1506). The write timeinformation is used by the control program 1126 to guarantee the writesequence when writing the write data to the remote copy destinationvolume.

The control program 1126 registers the information acquired in S1502(the write destination volume ID, the write address, the write datalength, and the write time information), the storage destination address(the write data pointer) of the cache memory that stored the write datain step S1504, and the sequential number denoting the update sequencefor the start of the remote copy in the write data management table 1125as a new entry (S1507). Furthermore, in a case where the write data hasbeen associated as being in need of a remote copy in S1506, the controlprogram 1126 registers the remote copy requirement 11257 of the writedata management table 1125 as remote copy required.

In the above-described process, the control program 1126 is able toasynchronously manage a write request from the host computer 30 a andstore write data from the cache memory in a volume by using the writedata management table 1125 to manage the write data, and storing thewrite data in the volume from the cache memory while referencing thistable 1125.

FIG. 16 is a flowchart of a write data transfer process of the firstexample.

The process for transferring write data from the primary storage system10 a to the secondary storage system 10 b is carried out here by thecontrol program of the primary storage system 10 a (hereinafter theprimary control program) 1126. Furthermore, the processing to the leftof the dotted line is primary storage system 10 a processing, and theprocessing to the right of the dotted line is secondary storage system10 b processing.

First, the primary control program 1126 identifies the entry (row) inthe write data management table 1125 in which the remote copyrequirement 11257 comprises “required”. Next, the primary controlprogram 1126 creates write data information based on the information ofthe identified entry, the write data management table 1125, the volumeset management table 1123, and the copy pair management table 1124(S1601).

The write data information comprises the following information:

-   -   the write destination address 11262, the write data length        11263, and the write time 11266 of the above-mentioned        identified row in the write data management table 1125; and    -   the partner storage ID 11244, the partner volume ID 11245, and        the partner volume set ID 21033 identified from the volume        management table 1121, the copy pair management table 1124, and        the volume set management table 2103.

For example, in a case where the volume ID 11251 registered in the writedata management table 1125 is “VOL D1”, the entry of the volume ID “VOLD1” is retrieved from the volume management table 1121. Then, using thepair ID 11216 of this entry, the information related to the pairconfiguration to which the “VOL D1” belongs (the partner storage ID11244, the partner volume ID 11245, and the partner volume set ID 21033)is identified from the copy pair management table 1124 and the volumeset management table 1123.

Next, the primary control program 1126 transfers the write dataidentified in S1601 and the created write data information to thesecondary storage system 10 b (S1602).

The control program of the secondary storage system 10 b (hereinafterthe secondary control program) 1126, upon receiving the write data andthe write data information from the primary storage system 10 a, storesthis information in the cache memory 113 (S1603). The secondary controlprogram 1126, based on the received write data information, registers anew entry in the write data management table 1125 of the secondarystorage system 10 b (S1604). The secondary control program 1126 checkswhether or not a write time is included in the received write datainformation (S1605). In a case where the write time is the latest writetime (S1605: Yes), the secondary control program 1126 registers thewrite time as the latest data reflection time 11236 in the volume setmanagement table 1123 of the secondary storage system 10 b (S1606).Furthermore, in a case where the write time is not the latest write time(S1605: No), the secondary control program 1126 performs the processingof S1607 and subsequent steps.

The secondary control program 1126 reports to the primary storage system10 a that the write data receive is complete (S1607).

The primary control program 1126, which received the write data receivecomplete report, updates the remote copy requirement 11257 of the writedata corresponding to the complete report to “not required” in the writedata management table 1125, and ends the processing (S1608).

Furthermore, in a case where the primary control program 1126 haschecked that the write data has been written to the volume (the remotecopy destination volume) of the secondary storage system 10 b, theprimary control program 1126 may delete the entry corresponding to theremote-copied write data from the write data management table 1125.

FIGS. 17 and 18 are flowcharts showing examples of the write datareflection process by the control program (for example, the secondarycontrol program) 1126 in the first example. Specifically, FIG. 17 is aflowchart of a write data reflection process performed by arepresentative storage system (for example, a representative secondarystorage system). FIG. 18 is a flowchart of a write data reflectionprocess performed by a non-representative storage system (for example, anon-representative secondary storage system).

A representative secondary storage system of the multiple secondarystorage systems 10 b controls the start of a reflection process ofanother secondary storage system. This makes it possible to guaranteethat write sequence in the copy source volume set and the reflectionsequence in the copy destination volume set are the same even when themultiple copy destination volumes comprising the copy destination volumeset reside in multiple secondary storage systems. Furthermore, a storagesystem that is not a virtual storage system may comprise a volume setincluded in a virtual volume set, and in this case, this one storagesystem may serve both as a representative storage system and as anon-representative storage system.

The control program of the representative storage system (hereinafter,the representative control program) 1126 identifies the ID of thestorage system comprising the volume set, which is the managementtarget, from the volume set representative management table 1122. Therepresentative control program 1126 also identifies the latest datareflection time 11236 of the management target volume set from thevolume set management table 1123, which all of the non-representativestorage systems have (S1701).

The representative control program 1126 selects the oldest time 11236from among all of the latest data reflection times 11236 identified inS1701, and registers the selected time 11236 as the container time 11222of the volume set representative management table 1122 (S1702). Inaddition, the representative control program 1126 instructs therespective non-representative storage systems (the non-representativestorage system comprising the volume set that is the management target)to reflect write data denoting a time that is older than this containertime 11222 in the copy destination volume, and waits for a reportrelated to the copy destination volume reflection processing from eachnon-representative storage system (S1703).

The representative control program 1126 receives a reflectionprocessing-related report from any of the non-representative storagesystems (S1704), and checks whether a write data reflection complete hasbeen received from all of the management target non-representativestorage systems (S1705). In a case where a reflection complete has beenreceived from all of the non-representative storage systems (S1705:Yes), the representative control program 1126 ends the processing. In acase where a reflection complete has not been received from at least oneof the non-representative storage systems (S1705: No), processingreturns to S1704, and the representative control program 1126 receivesthe reflection processing-related report from the non-representativestorage system.

Next, a write data reflection process in a non-representative storagesystem will be explained using FIG. 18.

The control program (hereinafter the non-representative control program)1126 of a non-representative storage system (for example, the secondarystorage system 10 b) receives a write data reflection instruction (referto S1703) from the representative storage system (S1801). Thenon-representative control program 1126 reflects the write data untilthe instructed time in the copy destination volume in the sequence ofthe sequential number 11255 from the write data management table 1125(S1802). When the write data reflection is complete, thenon-representative control program 1126 issues a write data completereport to the representative storage system (S1803).

FIG. 19 is a flowchart of a virtual volume set creation process of thefirst example. FIG. 20 is a diagram showing a virtual volume setcreation screen provided by the storage control program of the firstexample. The virtual volume set creation process will be explainedhereinbelow using FIGS. 19 and 20. The virtual volume set and the actualvolume set that comprise same are determined here.

The storage management program 2104 receives a virtual volume set createrequest from the user via a user interface (refer to FIG. 20) providedby the storage management program 2104 (S1901). The storage managementprogram 2104 displays the virtual volume set creation screen G2000 on adisplay device (not shown in the drawing) of the management computer 20(S1902). At this time, the storage management program 2104 displays inthe storage system field G20001 all of the storage IDs 21011 registeredin the storage management table 2101 as storage system selectioncandidates. According to the example of FIG. 12, the “Storage A”, the“Storage B”, and the “Storage C” are displayed as the selectioncandidates in the storage system field G20001.

Next, the user uses the input device (not shown in the drawing) of themanagement computer 20 to select, from among the one or more storage IDsdisplayed in the storage system field G20001, the ID of the storagesystem in which he wishes to create a virtual volume set (S1903).

The storage management program 2104 identifies the ID 21011 that matchesthe storage ID that the user selected in S1903 from the storagemanagement table 2101.

Next, the storage management program 2104 performs the followingprocessing in S1904:

-   -   identifies from the volume set consolidation management table        2103 the same storage ID 21032 as the identified storage ID        21011; and    -   displays in the added volume set field G20003 as a volume set        selection candidate the ID of the actual volume set, which        corresponds to the identified storage ID 21032, has        “unregistered” as the partner volume set ID 21033, and, in        addition, does not comprise a virtual volume set.

The user inputs the ID of the newly created virtual volume set to thevirtual volume set field G20002 (S1905), and selects the volume setregistered in the virtual volume set from the added volume set fieldG20003 (S1906).

The storage management program 2104 references the storage managementtable 2101, identifies the representative storage system of the storagesystem comprising the storage system selected by the user in S1903, andsends a volume set registration request to this representative storagesystem. The representative storage system that receives this requestregisters an entry related to the newly created volume set in the volumeset representative management table 1122 (S1907). The storage managementprogram 2104 at this point registers the ID of the virtual volume setand the ID of the volume set comprising same.

Lastly, the storage management program 2104 registers an entry relatedto the newly created virtual volume set in the volume set consolidationmanagement table 21023. Specifically, the storage management program2104 changes the configuration status 21037 of the volume set includedin the virtual volume set to “ON”, and, in addition, registers the ID ofthe created virtual volume set as the virtual volume set ID 21038(S1908).

FIGS. 21 to 23 are flowcharts showing an example of a remote copy paircreation process in the first example. Furthermore, FIG. 24 is a diagramshowing an example of a remote copy screen in the first example. Theremote copy pair creation process will be explained by referring to theFIGS. 21 to 24.

The storage management program 2104 receives a remote copy pair createrequest from the user via a user interface provided by the storagemanagement program 2104 (S2101). The storage management program 2104displays a remote copy pair creation screen G2200 in response to thisrequest (S2102). The storage management program 2104 displays all of thestorage IDs 21011 registered in the storage management table 2101 in aremote copy source storage system field G22001 at this time.

The user selects the storage system he wishes to use as the remote copysource from among the storage systems displayed in the remote copysource storage system field G22001 (S2103).

The storage management program 2104, based on the volume consolidationmanagement table 2103, lists up the volumes, which are in the storagesystem that the user selected in S2103, and, in addition, which have“actual” as the volume type, and displays the IDs of all the volumesthat have been listed up (the volume selection candidates) in a remotecopy source volume field G22002 (S2104).

The user selects the volume he wishes to use as the remote copy sourcevolume from among the volumes displayed in the remote copy source volumefield G22002 (S2105).

The storage management program 2104, based on the volume setconsolidation management table 2103, lists up the volume sets in thestorage system comprising the volume that the user selected in S2105.Then, the storage management program 2104 displays the IDs of the volumesets that have been listed up (the volume set selection candidates) in aremote copy source volume set field G22003 (S2106).

The user selects the volume set comprising the volume selected in S2105from among the volume sets displayed in the remote copy source volumeset field G22003 (S2107).

For example, in a case where the user has selected the storage system“Storage A” in S2103, in S2104, the storage management program 2104displays all the volume IDs having the volume type “actual” from amongthe volumes of the storage system “Storage A” in the remote copy sourcevolume field G22002.

When the user selects the volume “VOL D1”, the storage managementprogram 2104 displays the volume set “Set D” of the storage system“Storage D” in the remote copy source volume set field G22003.Furthermore, according to the example of FIG. 24, a virtual volume setID may be displayed to clearly show which virtual volume set comprisesthe volume set “Set D”.

Next, as shown in FIG. 22, the storage management program 2104references the volume set consolidation management table 2103 to checkwhether a partner volume set (a copy destination volume set)corresponding to the volume set selected in S2107 has been registered(S2108).

For example, according to the example of FIG. 14, it is clear that whenthe user selected the volume set “Set D” in S2107, the partner volumeset “Set F” was registered.

In a case where the partner volume set is registered (S2108: Yes), thestorage management program 2104 displays the ID of the partner storagein a remote copy destination storage system field G22004, and, inaddition, displays the ID of the partner volume set in a remote copydestination volume set field G22006 (S2109).

Furthermore, in this example, the ID displayed in the remote copydestination storage system field G22004 may be the storage systemcomprising the virtual volume set, that is, the ID of the virtualstorage system. It can be supposed that this ID is the storage ID 21032in the entry comprising the volume set ID 21031 corresponding to thevirtual volume set ID 21038 of the volume set consolidation managementtable 2103.

Next, the storage management program 2104 displays an unused volume fromamong the volumes of the storage system comprising the volume setdisplayed in S2109 in a remote copy destination volume field G22005(S2110).

The user selects the volume he wishes to use as the remote copydestination volume from among the volumes displayed in the remote copydestination volume field G22002 in S2110 (S2111).

The storage management program 2104 sends an initial copy start requestto the storage system comprising the remote copy source volume, and tothe storage system comprising the remote copy destination volume(S2112).

Lastly, the storage system, which receives the initial copy startrequest, performs the following processing in S2113:

-   -   adds an entry related to the new remote copy pair to the remote        copy pair management table 1124;    -   updates the volume ID 11233 of the relevant volume set, the        partner storage ID 11234, and the partner volume set ID 11235 of        the volume set management table 1123;    -   updates the pair ID 11216 of the relevant volume of the volume        management table 1121; and    -   starts the initial copy subsequent to this processing.

In a case where it was determined in S2108 that there is no partnervolume set (S2108: No), the processing shown in FIG. 23 is performed.

Specifically, the storage management program 2104 identifies the virtualvolume set comprising the volume set that the user selected in S2106,and checks whether or not a partner volume set corresponding to thisvirtual volume set has been registered (S2115).

In a case where the partner volume set is registered (S2115: Yes), thestorage management program 2104 executes the processing of S2116 toS2120. In a case where the partner volume set is not registered (S2115:No), the storage management program 2104 executes the processing ofS2121 to S2126.

The storage management program 2104 identifies the ID 21034 of thepartner storage system comprising the virtual volume set identified inS2115 from the volume set consolidation management table 2103. Then, thestorage management program 2104 displays this ID in the remote copydestination storage field G22004 (S2116).

Next, the storage management program 2115, based on the volumeconsolidation management table 2102, displays the ID of the volume ofthe partner storage identified in S2116 (the remote copy destinationvolume selection candidate) in the remote copy destination volume fieldG22005 (S2117).

The user selects the volume he wishes to use as the remote copydestination volume from among the volumes displayed in the remote copydestination volume field G22002 (S2118).

The storage management program 2104 identifies the ID 21036 of thevolume set comprising the virtual volume set identified in S2115 fromthe volume set consolidation management table 2103.

The storage management program 2104 displays the ID of the volume set,which is in the storage system comprising the volume that the userselected in S2118, and, in addition, has yet to become a pair (theremote copy destination volume set selection candidate) of theidentified volume set ID 21036 in the remote copy destination volume setfield G22006 (S2119).

The user selects the volume set he wishes to use as the remote copydestination volume from among the volume sets displayed in the remotecopy destination volume set field G22006 (S2120).

In a case where the partner volume set is not set in S2115 (S2115: No),the processing hereinbelow is executed.

The storage management program 2104 displays the ID of a storage systemother than the storage systems that the user selected in S2103 (theremote copy destination storage system selection candidate) from thestorage management table 2101 in the remote copy destination storagesystem field G22004 (S2121). According to the example of FIG. 12, inS2104, when the remote copy source storage system “Storage A” has beenselected, the “Storage B” and the “Storage C” are displayed as thestorage systems other than the storage system “Storage A” in the remotecopy destination storage system field G2200.

The user selects the storage system he wishes to use as the remote copysource from among the storage systems displayed in the remote copysource storage system field G22001 (S2122).

The storage management program 2104, based on the volume consolidationmanagement table 2103, lists up the IDs of the volumes, which belong tothe storage system selected by the user in S2122, and, in addition, have“actual” as the volume type. The storage management program 204 displaysthe IDs of the volumes that have been listed up (the volume selectioncandidates) in the remote copy destination volume field G22005 (S2123).

The user selects the volume that he wishes to use as the remote copysource volume from among the volumes displayed in the remote copydestination volume field G22005 (S2124).

The storage management program 2104, based on the volume setconsolidation management table 2103, lists up the volume sets in thestorage system comprising the volume selected by the user in S2105.Then, the storage management program 2104 displays the IDs of the volumesets that that have not become pairs yet (the volume set selectioncandidates) from among the listed volume sets in the remote copydestination volume set field G22006 (S2125).

The user selects the volume set he wishes to use as the remote copydestination volume set from among the volume sets displayed in theremote copy destination volume set field G22006 (S2126).

Subsequent to the completion of the processing of either S2120 or S2126,the following processing is executed.

The storage management program 2104 updates the volume set consolidationmanagement table 2103 based on the setting contents of the screen G2200(S2127). Specifically, the storage management program 2104 updates thepartner volume set ID 21033 and the partner storage ID 21034 of therelevant volume set in a case where a partner volume set and a partnerstorage corresponding to each volume set have been newly determined.

The storage management program 2104 sends an initial copy start requestto the storage system comprising the remote copy source volume, and tothe storage system comprising the remote copy destination volume(S2128).

Lastly, the storage system that received the initial copy start requestin S2119:

-   -   adds an entry related to the new remote copy pair to the remote        copy pair management table 1124;    -   updates the volume ID 11233 of the relevant volume set, the        partner storage ID 11234, and the partner volume set ID 11235 of        the volume set management table 1123;    -   updates the pair ID 11216 of the relevant volume of the volume        management table 1121; and    -   starts the initial copy subsequent to this processing.

Furthermore, although omitted from the explanation, in S2119 and thelike, in a case where the relevant volume is not registered, an errornotification may be issued and the processing ended.

In the processes described hereinabove, when the remote copy destinationstorage system selection candidates are listed up (S2121), for example,a storage system included in the same virtual storage system as theremote copy source storage system will not be listed up as a remote copydestination storage system selection candidate even when the storagesystem differs from the remote copy source storage system. For thisreason, it is possible to prevent the creation of a remote copy pairbetween storage systems included in the same virtual storage system.That is, the virtual storage system can be managed as a single storagesystem.

Furthermore, in the remote copy pair creation process in this example,when the remote copy source volume selection candidates and the remotecopy destination volume selection candidates are listed up (S2105,S2110, S2117, S2123), only those volumes with the volume type “actual”are listed up. For this reason, it is possible to restrict the remotecopy pair components to actual volumes even when a virtual volume thatis associated with an actual volume exists, and the virtual volume isbeing provided to the host computer.

Furthermore, both a virtual volume and an actual volume may be displayedas a remote copy source volume selection candidate and/or a remote copydestination volume selection candidate. In a case where a virtual volumehas been selected as the remote copy source volume and/or the remotecopy destination volume, the volume consolidation management table 2102can be used to identify the actual volume that corresponds to thevirtual volume. That is, in a case where the remote copy source volumeand/or the remote copy destination volume is/are a virtual volume, theassociated actual volume substantially becomes the remote copy sourcevolume and/or the remote copy destination volume.

Furthermore, in the processes described hereinabove, the premise is thatan actual volume set is included in a virtual volume set beforehand, andwhen creating a remote copy pair, the user must be aware of the actualvolume sets that comprise the virtual volume set.

However, for example, only the virtual volume set itself may bespecified without specifying the actual volume sets that are included inthis virtual volume set. In accordance with this, the storage managementprogram 2104 must perform the following checks with respect to thestorage system comprising the remote copy source volume and/or thestorage system comprising the remote copy destination volume:

(A) check whether or not an actual volume set comprising the specifiedvolume is included in the specified virtual volume; and

(B) check whether or not the volume set comprising the remote copysource volume and the volume set comprising the remote copy destinationvolume are associated with one another.

The storage management program 2104, in a case where the check resultfor at least one of the above-mentioned (A) and (B) is negative, is ableto create a new volume set, include this volume set in the virtualvolume set, and create a new pair (volume set pair). By doing so, theuser need not be made aware of the actual volume sets that are includedin the virtual volume set when a remote copy pair is created.

FIG. 25 is a flowchart of a storage addition process of the firstexample. Furthermore, FIG. 26 is a diagram showing a storage additionscreen of the first example. The storage addition process will beexplained by referring to FIGS. 25 and 26.

The storage management program 2104 receives a storage addition requestfrom the user via a user interface provided by the storage managementprogram 2104 (S2301). Then, the storage management program 2104 displaysa storage addition screen G2400 in response to this request (S2302).

The storage management program 2104 displays the IDs of storage systemshaving a scale-out availability of “ON” (virtual storage selectioncandidates) based on the storage management table 2101 in an adddestination virtual storage ID field G24001.

In addition, the storage management program 2104, based on the storagemanagement table 2101, displays the IDs of storage systems for which thescale-out availability is “ON” and the virtual storage system comprisesonly one storage system in a storage system to be added field G24002.

Next, the user selects the ID of the virtual storage system to which hewishes to add a storage system from among the storage systems displayedin the add destination virtual storage ID field G24001 (S2303).Furthermore, the user may not only select a storage ID from the adddestination virtual storage ID field G24001, but may also directly inputa storage ID into the add destination virtual storage ID field G24001 tohandle a case in which a new virtual storage is created.

In addition, the user selects the ID of the storage system he wishes toadd to the virtual storage system that the user selected in S2303 fromthe storage systems displayed in the storage system to be added fieldG24002 (S2304).

The storage management program 2104 identifies ID 21013 of the storagesystems that comprise the virtual storage system selected by the user inS2303 from the storage management table 2101 (S2305).

The storage management program 2104, based on the copy pair managementtable 1124 of the storage system selected in S2304, checks for thepresence or absence of a remote copy pair from this storage system tothe respective storage systems identified in S2305 (S2306). That is, thestorage management program 2104 checks whether or not the IDs of thestorage systems identified in S2305 are in the copy pair managementtable 1124 of the storage systems selected in S2304 as partner storageIDs.

In a case where a remote copy pair does not exist (S2306: Yes), thestorage management program 2104, based on the copy pair managementtables 1124 of the respective storage systems acquired in S2305, checksfor the presence or absence of remote copy pairs from the storage systemselected in S2304 to the respective storage systems (S2307). That is,the storage management program 2104 checks whether or not the ID of thestorage system selected in S2304 is in the copy pair management tables1124 of the respective storage systems as the partner storage ID.

In a case where the remote copy pair does not exist (S2307: Yes), it issupposed that a storage add is allowed, and the storage managementprogram 2104 updates the storage management table 2101 and ends theprocessing (S2308).

In cases where a remote copy pair exists in S2306 and S2307 (S2306: No,S2307: No), a storage add cannot be allowed, and as such, the storagemanagement program 2104 notifies the user of an error and ends theprocessing (S2309).

Furthermore, when a storage addition is successful, the storagemanagement program 2104 redefines the representative storage system suchthat there is only one representative storage system in the virtualstorage system. Furthermore, the storage management program 2104consolidates the volume set representative management table that theadd-target storage system possessed from before the addition of thestorage system together with the volume set representative managementtable that the representative storage system of the virtual storagesystem possessed prior to the addition.

As in the above-described processes of S2306 and S2307, a check isperformed as to whether or not an identified condition is being met (inS2306 and S2307, a check as to whether or not a remote copy pair existsbetween the storage systems that comprise the virtual storage system andthe newly added storage system), and the storage addition is onlyallowed when the condition is satisfied. Consequently, a problematicconfiguration can be prevented.

According to the first example described hereinabove, the addition of astorage is allowed only in a case where a remote copy pair does notexist between a storage system that is already included in the virtualstorage system and the storage system to be added anew. This makes itpossible to prevent a remote copy pair from being formed in the samevirtual storage system.

FIG. 27 is a flowchart of a failover requirement determination processof the first example.

A failover requirement determination process is for determining whetheror not it is necessary to switch operations to the secondary storagesystem when the primary storage system included in the primary-sidevirtual storage system has been damaged.

In a case where a damaged storage system is one of the storage systemsincluded in a virtual storage system, a failover may not be necessarywhen the storage system comprising the volume in which the actual datais being stored has not been damaged.

FIG. 31 is a diagram showing an example of the configuration of astorage system for which a failover is not required in the firstexample.

According to the example of FIG. 31, the situation is one in which avirtual storage system Z of the storage systems that are included in aprimary storage system V is damaged. However, storage systems Y and X,which comprise actual volumes that belong to a volume set V, are notdamaged, and the data can be accessed normally. For this reason, it isnot necessary to execute a failover.

A situation like this will occur in a case where the primary storagesystem Z, which comprises the virtual volume, is subsequently added tothe primary storage system V comprising the primary storage system Y andthe primary storage system X, which comprise actual volumes, and a pathto the primary storage system V by way of the primary storage system Z,which comprises the virtual volumes, has been added.

When the storage system is damaged, in a case where a function forexecuting the failover requirement determination process has beenprovided in the storage management program 2101, it is possible todetermine whether or not a failover is necessary, and to present theuser with this result. In accordance with this function, the user isable to check the fact that the storage system is damaged, and whetheror not a failover must be executed as a result of this damage. Thisprocess will be explained below using the flowchart of FIG. 27.

The storage management program 2104, upon detecting that a storagesystem has been damaged (S2501), identifies the virtual storage systemcomprising the damaged storage system based on the storage managementtable 2101. Furthermore, the storage management program 2104 is able todetect whether or not a storage system has been damaged by regularlycommunicating with the storage system to check that communications arepossible.

In addition, the storage management program 2104, based on the volumeset consolidation management table 2103, identifies the virtual volumeset of the relevant virtual storage system, and the volume set includedin the virtual volume set (S2502).

The storage management program 2104 identifies the volumes allocated tothe respective volume sets included in the virtual volume set identifiedin S2502 from the volume set management table 1123 of the storage systemcomprising the respective volume sets (S2503).

The storage management program 2104, based on the actual storage ID21024 corresponding to the volume identified in S2503 in the volumeconsolidation management table 2102, checks whether a volume thatbelongs to the damaged storage system exists among the volumesidentified in S2503 (S2504).

In a case where a volume belonging to the damaged storage exists inS2504 (S2504: Yes), the storage management program 2104 notifies theuser that failover is required and ends the processing (S2508).

In a case where a volume belonging to the damaged storage does not existin S2504 (S2504: No), the storage management program 2104 notifies theuser that failover is not required and ends the processing (S2509). Theuser will instruct a failover in accordance with the notification.

According to the first example described hereinabove, the storagesystems that are included in the same virtual storage can be managed asa single storage system. According to the first example, it is possibleto prevent a remote copy pair from being formed between the storagesystems included in the same virtual storage system.

Furthermore, even in a case where a volume set spanning the storagesystems included in the same virtual storage system has been defined, itis possible to guarantee that the write update sequence to theprimary-side volume and the write reflection sequence to thesecondary-side volume are the same.

Furthermore, in this example, even in a case where a volume set spanningmultiple storage systems has been defined, it is possible to guaranteethat the write update sequence to the primary-side volume and the writereflection sequence to the secondary-side volume are the same byproviding a representative storage system that controls the start of thewrite data reflection process to the secondary-side volume. That is, anarbitrary volume can be registered in the same volume set even in avirtual storage system (a scale-out storage system).

However, guaranteeing that the write update sequence and the writereflection sequence are the same may also be done by arranging all ofthe volumes defined in the same volume set in the same storage system.That is, the configuration may be such that the storage managementprogram 2104 comprises a function for issuing an instruction to migratethe data of a certain volume to another volume, and a single storagesystem holds all of the remote copy source volumes (remote copydestination volumes). Since this enables the storage management program2104 to issue an instruction to the control program to migrate thevolume data to an identified storage system prior to sending the controlprogram the initial copy execution instruction when a remote copy paircreate instruction has been received from the user, the write updatesequence and the write reflection sequence can be made the same.

Example 2

In a second example, a stand-alone management computer 60 is disposed ina one-to-one relationship with respect to each storage system 10 a and10 b. The respective storage systems 10 a and 10 b are managed by themanagement computer 20 and the respective stand-alone managementcomputers 60 (Refer to FIG. 28).

In a case where there is a stand-alone management computer 60 formanaging a single storage system like this, the stand-alone managementcomputer 60, by executing an illegal storage management, could wind upcreating an illegal configuration in the computer system 1.

A process for detecting this kind of illegal configuration and notifyingthe user will be explained below. As used here, illegal storagemanagement and illegal configuration signify the formation of a remotecopy pair between storage systems included in the same virtual storagesystem. Furthermore, only the differences with respect to the firstexample will be explained in this example.

FIG. 28 shows an example of the configuration of the computer system 1of the second example.

The difference with the first example, as mentioned above, is that astand-alone management computer 60 is provided for each storage system10 a and 10 b.

The management computer 20 and the stand-alone management computers 60coexist in the computer system 1 of the second example. The managementcomputer 20 mainly manages the multiple storage systems 10 a and 10 b.The stand-alone management computer 60 mainly manages the individualstorage systems 10 a and 10 b.

FIG. 29 shows an example of the configuration of the stand-alonemanagement computer 60 of the second example.

The hardware configuration of the stand-alone management computer 60 ispractically the same as that of the management computer 20 of the firstexample, but the programs stored in the memory 610 differ. The programsstored in the memory 610 are a stand-alone storage management program6101 for managing an individual storage system, and an OS 6102 forcontrolling the stand-alone storage management program 6101.

The stand-alone storage management program 6101 is used by the user toinstruct the control program 1126 of the management target storagesystem via a user interface provided by the stand-alone storagemanagement program to create a remote copy pair.

For example, when a request to create a remote copy pair from a volumeof the management target storage system to a volume of a storage systemcoupled to this storage system is issued to the control program 1126,the control program 1126 updates the volume management table 1121, thevolume set management table 1123, and the copy pair management table1124 based on the instructed pair information, and starts the remotecopy. However, the stand-alone management computer 60 is unable tocollectively manage multiple storage systems, and does not manage thestorage configuration related to a scale-out, such as a virtual storagesystem and the storage systems that comprise same.

For this reason, there may be cases in which a remote copy pair isformed between storages that are included in the same virtual storagesystem.

FIG. 30 is a flowchart of a configuration error determination process ofthe second example.

A configuration error determination process is one that determineswhether there is a remote copy pair between storages included in thesame virtual storage system.

The storage management program 2104 identifies the storage systemsincluded in the virtual storage system based on the storage managementtable 2101 (S2801). Next, the storage management program 2104 checkswhether or not the copy pair management table 1124 information wasacquired with respect to the all the storage systems acquired in S2801(S2802).

In a case where the information of the copy pair management table 1124has not been acquired with respect to all of the storage systems (S2802:No), the storage management program 2104 acquires the information of thecopy pair management table 1124 from the storage systems with respect towhich this information has not been acquired (S2803). In a case wherethe information of the copy pair management table 1124 has been acquiredwith respect to all of the storage systems (S2802: Yes), the storagemanagement program 2104 performs the processing of S2805 and subsequentsteps.

The storage management program 2104 acquires the ID registered in thepartner storage ID 11243, which is the copy destination, for each pair(each pair registered in the copy pair management table 1124 acquired inS2803).

Next, the storage management program 2104, based on the storagemanagement table 2101, determines whether or not the storage system(s)from which the copy pair management table(s) 1124 were acquired in S2803and the storage system(s) identified from the acquired ID(s) arestorages that are included in the same virtual storage system, and ifthe storages are included in the same virtual storage system, holds thepair information as a configuration error (S2804).

In a case where it has been determined in S2802 that copy pairinformation tables have been obtained from all the storage systems(S2802: Yes), the storage management program 2104 checks for thepresence or absence of a pair that has been registered as aconfiguration error in S2804 (S2805).

In a case where there is a pair that has been registered as aconfiguration error (S2805: Yes), the storage management program 2104presents the relevant pair to the user as a configuration error, andends the processing. In a case where in S2805 no pair has beenregistered as a configuration error (S2805: No), the storage managementprogram 2104 ends the processing as-is.

In the above-described processing, the storage management program 2104checks for the presence or absence of a configuration that satisfies aspecific condition (S2804), and in a case where a configuration thatmeets the condition is discovered, presents same to the user as aconfiguration error (S2806). In accordance with to this process, theuser is able to check for a specific configuration status in thecomputer system 1, and to make a determination as to whether or not aconfiguration revision is necessary.

According to the second example described hereinabove, even in a casewhere the computer system comprises an illegal configuration, such asthe formation of a remote copy pair between storage systems that areincluded in the same virtual storage system, this illegal configurationcan be detected and presented to the user.

A number of examples of the present invention have been explainedhereinabove, but these are examples for illustrating the presentinvention, and do not purport to limit the scope of the presentinvention to these examples. The present invention can be put intopractice in a variety of other modes.

For example, it is possible to avoid a situation in which a copy sourcevolume, which comprises a remote copy pair with a copy destinationvolume, exists in the virtual storage system comprising this copydestination volume.

REFERENCE SIGNS LIST

-   1 Computer system-   10 a Primary storage system-   10 b Secondary storage system-   20 Management computer

The invention claimed is:
 1. A management system coupled to a storagesystem group comprising a plurality of storage systems including aplurality of logical volumes, the storage system group including avirtual storage system, which is a scale-out storage system that isconfigured by more than one of the plurality of storage systems, themanagement system comprising: an interface device, which is coupled tothe storage system group; a processor, which is coupled to the interfacedevice; and a storage resource storing instructions that are executableby the processor to manage one or more volume sets formed by plurallogical volumes among the plurality of logical volumes, wherein theprocessor is configured to execute the instructions stored by thestorage resource to: receive a remote copy pair create instruction froma user, and migrate a target logical volume of a target logical volumeset among the volume sets, to an identified storage system so that theidentified storage system includes all logical volumes of the targetlogical volume set, wherein the target logical volume is a copy sourcevolume or a copy destination volume, and wherein all logical volumes ofthe target logical volume set are copy source volumes or copydestination volumes.
 2. A management system according to claim 1,wherein: the processor is further configured to execute the instructionsstored by the storage resource to: execute an initial copy which is tocopy all data in a copy source volume selected in response to the remotecopy pair create instruction to a copy destination volume selected inresponse to the remote copy pair create instruction, and migrate thetarget logical volume before executing the initial copy.
 3. A managementsystem according to claim 1, wherein: the target logical volume is alogical volume selected as a copy source volume in response to theremote copy pair create instruction, or any copy source volume otherthan the target logical volume of the target logical volume set.
 4. Amanagement system according to claim 1, wherein: the target logicalvolume is a logical volume selected as a copy destination volume inresponse to the remote copy pair create instruction, or any copydestination volume other than the target logical volume of the targetlogical volume set.
 5. A management system according to claim 1,wherein: the storage resource stores volume management informationincluding information denoting which storage system includes whichlogical volume, the storage resource stores volume set managementinformation including information denoting which volume set is formed bywhich plural logical volumes, and the processor is further configured toexecute the instructions stored by the storage resource to: migrate thetarget logical volume based on the volume management information and thevolume set management information.
 6. A management system according toclaim 1, wherein: the storage resource stores, for each of the storagesystems, storage management information denoting whether or not arespective storage system is a component of the virtual storage system,and the processor is further configured to execute the instructionsstored by the storage resource to: (a) determine, based on the storagemanagement information, whether or not a first storage system is acomponent of the virtual storage system, (b) identify, based on thestorage management information, a second storage system, which is not acomponent of the virtual storage system including the first storagesystem in a case where the result of the determination in (a) isaffirmative, and (c) allow a user to configure a remote copy pair thatuses a logical volume as either a copy source volume or a copydestination volume only with respect to the second storage system,wherein the remote copy pair is a pair of a logical volume of the firststorage system and the logical volume of the second storage system, andthe logical volume of the first storage system is either the copydestination volume or the copy source volume, respectively.
 7. Amanagement system according to claim 6, wherein: the processor, in acase where a failure has been detected in a certain storage system, isfurther configured to execute the instructions stored by the storageresource to: (p) identify the virtual storage system that includes thecertain storage system based on the storage management information, (q)identify a volume set of the virtual storage system, (r) determinewhether or not an actual volume in any of the identified volume setsexists in the certain storage system, and (s) output informationdenoting that a failover is necessary when the result of thedetermination in (r) is affirmative, and output information denotingthat a failover is not necessary when the result of the determination in(r) is negative.
 8. A method of managing a storage system groupcomprising a plurality of storage systems including a plurality oflogical volumes, the storage system group including a virtual storagesystem, which is a scale-out storage system that is configured by morethan one of the plurality of storage systems, the method comprising:receiving a remote copy pair create instruction from a user, andmigrating a target logical volume of a target logical volume set amongvolume sets, to an identified storage system so that the identifiedstorage system includes all logical volumes of the target logical volumeset, wherein each of the volume sets is formed by plural logical volumesamong the plurality of logical volumes, the target logical volume is acopy source volume or a copy destination volume, and all logical volumesof the target logical volume set are copy source volumes or copydestination volumes.
 9. A non-transitory computer readable medium havingan executable program thereon for managing a storage system groupcomprising a plurality of storage systems including a plurality oflogical volumes, the storage system group including a virtual storagesystem, which is a scale-out storage system that is configured by morethan one of the plurality of storage systems, the executable programcausing a computer to perform a method comprising: receiving a remotecopy pair create instruction from a user, and migrating a target logicalvolume of a target logical volume set among volume sets, to anidentified storage system so that the identified storage system includesall logical volumes of the target logical volume set, wherein each ofthe volume sets is formed by plural logical volumes among the pluralityof logical volumes, wherein the target logical volume is a copy sourcevolume or a copy destination volume, and wherein all logical volumes ofthe target logical volume set are copy source volumes or copydestination volumes.